<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="hello.css">
    <title>Document</title>
</head>
<body>
    <h1> 使用LESS </h1>
    <div id="box">
        一个盒子
    </div>

    <h1>嵌套</h1>
    <header>
        <div class="logo">LOGO图片</div>
        <div class="nav">导航条</div>
    </header>
</body>
</html>